1. Field of the Invention
The present invention relates to an electronic switch, Which comprises a pair of self arc-suppressing elements connected in inverse-series between a pair of terminal portions to which AC power is applied through a load and which turns on or turns off the pair of self arc-suppressing elements in accordance with a phase control signal.
2. Description of the Related Art
FIG. 29 is a circuit diagram illustrating a conventional electronic switch. The electronic switch shown in FIG. 29 is provided between an AC power source AC and a load LD, and adjusts the power supply to the load LD from the AC power source AC by means of phase control. Here, the electronic switch comprises a pair of terminal portions 14, 14, a triac T connected therebetween, a diac Dk, and a volume resistor VR for adjusting a phase control angle, and turns on or turns off the triac T by means of the phase control. Further, in FIG. 29, a noise filter comprising capacitors Ca, Cb, a resistor Ra, and an inductor La is provided.
Further, an illuminating equipment comprising a serial circuit of switching elements IGBTs connected in inverse-series, two diodes connected in inverse-parallel between the drain and the source of each switching element, and an illuminating load connected to both ends of an AC power source through a serial circuit of two switching elements is disclosed in Japanese Patent Unexamined Publication JP-A 7-296971(1995). However, since the conventional electronic switch employs a triac for holding an electrical connection until current therethrough becomes zero, the conventional electronic switch has a problem that overcurrent cannot be released instantly from flowing, even when the overcurrent is detected and a driving signal of the triac is switched into stop.